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Technologies in Physical Rehabilitation of CP Patients - Featured December 31, 2010

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Technologies in Physical Rehabilitation of CP Patients

By: Alan Waterman and Avraham Cohen (MediTouch Ltd, Israel)

The prevalence of Cerebral Palsy (CP) in the USA is approximately 1.5-2 cases per 1000 live births. Of this group about 20-30% of patients suffer from Hemiplegia or double Hemiplegia with arm movement dysfunction being more impaired than the legs. CP patients experience difficulty when reaching for and gripping objects, as well as replacing and releasing objects with the task being performed with uncoordinated, non-fluid and slow inaccurate movements.

There are two fundamental targets for physical rehabilitation exercises. The first is that exercises have to be tailored to a level slightly above the patients’ movement ability. This provides the patient with motivation. The second element is to involve the patients in their own rehabilitation.

The challenge for physical and occupational therapists and the rehabilitation equipment industry is to find effective interventions and tools that will improve arm and hand function for patients with moderate to severe hand motor deficit and paresis.

In regards to upper limb rehabilitation, traditional occupational and physical therapy mainly provides the patient with task orientated training (TOT) also known as Task Specific Practice (TSP) or Functional Movement Training (FMT). TSP is intensive repetition of everyday functional tasks or Active Daily Living (ADL) tasks.

The difficulty posed to therapists is to customize the TSP to the patient’s motor ability and devise a motivating intensive therapy session for the patient.

Constraint Induced Movement Therapy (CIMT) is considered an early, intensive and task specific approach to neurological rehabilitation. As we know CIMT works by constraining the non impaired hand and forces the patient to use only the affected hand to do a task. In this way the patient does not rely on the healthy hand to perform the task. CIMT therefore ensures that the patient performs intensive and repetitive functional tasks.

However, in order to do ADL tasks a person has to have a level of sensory, motor and cognitive ability that enables him to move limbs actively against resistance. Even the simple function of holding a book in one hand requires the patient to have sufficient movement ability to grasp and hold the book. Movement abilities such as active range of motion, strength, sensory and cognitive ability have to be at a sufficient level, therefore, that will enable the accomplishment of the task. This makes it difficult for the therapist to find intensive repetitive tasks that can be adapted to the patients’ active movement ability and remain challenging and motivating enough in order for the patient to do intensive repetitions of the task.

Because of the inclusion criteria, immobilizing the non affected arm is not effective with severely impaired patients. Therefore, alternative treatments to CIMT are needed which target more impaired subjects.

As stated earlier, it is well understood that the underlying principle of physical rehabilitation is intensive active exercise practice. In the December edition of Current Opinion in Neurology Dr. Brochard of the Service Médecine Physique et de Réadaptation, Brest, France discusses ''What’s new in new technologies for upper extremity rehabilitation'' http://bit.ly/h5UI0b

The author concludes that the contribution to clinical practice currently is the provision of intensive, repetitive movements.

In the October edition of Physical Therapy Dr. Ulrich and her team at Developmental Neuromotor Control Laboratory University of Michigan discuss opportunities for Early Intervention Based on Theory, Basic Neuroscience, and Clinical Science http://bit.ly/hW2tH5

The team concludes that therapeutic approaches in the pediatric population have generally been less aggressive than those implemented for younger and older adults. They suggest that caregivers and therapists should learn how to implement intervention programs focused on the development of specific functional skills. . However they point out that it is not easy to engage younger children in tasks that are painful or do not motivate the child.

So what options exist for pediatric patients with moderate and severe motor deficit?

In order to answer this question, we need to first recap the four categories of exercise therapy.
They are:
  1. Passive: An outside force moves the limb
  2. Assisted active: an outside force moves the limb with the patient attempting to aid this movement
  3. Active: The patient independently moves the limb
  4. Active against resistance: The patient moves the limb against an external force.


Following this we need to review the state of the art in terms of modern rehabilitation tools. There are several common rehabilitation methods including robotic assisted training tools, Electromyography (EMG), Functional Electrical Stimulation (FES) and TSP. These techniques and tools are used by therapists to encourage active movement practice.

EMG is used to enable patients to control their muscle activity and encourage active movement ability. EMG uses biofeedback to make the patient aware when they are contracting muscle fibers even though this contraction does not necessarily produce enough strength to flex or extend the joint.

Robotic assisted tools use mechanical motors to move the patient's limb. These robotic tools incorporate force sensors and varying numbers of limb movement sensors. The software uses motion feedback to encourage the patient to work with the external force moving the limb. If the robot’s motor gives the patient movement assistance in the preferred direction the exercise task is classified as “assisted active exercise”. If the motor is used to give a resistance force against the direction of movement then the exercise is classified as “active resistance”.

Advanced robotic training tools have integrated sensors that measure the position of each joint. In addition, the rehabilitation software has been clinically based to ensure that the repetitive arm movement pattern implements, as near as possible, a correct movement pattern. The motion feedback information derived from the patients individual joint movement is used to teach the patient the correct movement pattern. This allows for intensive repetitions to be practiced with minimum compensatory movements.

However some robotic tools can only detect the end point of the movement or the end point in space to be reached by the limb as they perform the virtual task. End point feedback does not give an indication of the quality of the task and therefore the patient can accomplish it with a less efficient pattern that involves a large amount of movement compensation.

Although few research articles have been published in regards to the rehabilitation outcomes of robotic training in pediatrics, a recent article in the November edition of European Journal of Pediatric Neurology found that Children and adolescents with bilateral spastic cerebral palsy showed improvements in the functional tasks of standing and walking after a 3-week trial of robotic-assisted treadmill therapy. The report was written by Borggraefe and his team at the Department of Pediatric Neurology Dr. von Haunersches Children's Hospital University of Munich Germany and Dr Dabrowski at Children's Hospital of Michigan, Detroit http://bit.ly/h5UI0b

FES uses muscle stimulation to contract the muscle and generate sufficient force to flex or extend the limb. In order to transform this technique to active exercise the therapist needs to encourage the patient to flex or extend their limb in conjunction with the appropriate stimulation.

TSP involves the adaptation of an Active Daily Living (ADL) task such as reaching or drinking. Depending on the patient's ability, the therapist can choose which exercise category the patient needs to practice. They can first work on passive exercise of the arm. This can be followed by assisted active drinking practice with the help of the therapist. Finally the patient can practice reaching and making a drinking movement by themselves. By using different cups and bottles correction feedback will be provided by the objects used for the task.

However if the patient does not have the minimum level of movement ability to do the ADL task then augmented feedback is required. For example, if the patient can not grasp because of insufficient hand range of motion then the therapist needs to improve the patient's ability as a component of the ADL drinking task. This is achieved by focusing on the movement of the impaired joint and providing relevant feedback.

Recently a new group of rehabilitation tools that incorporate the concept of Impairment Oriented Training (IOT) and augmented feedback software has been introduced. This group is used to promote upper limb recovery in neurological and orthopedic patients including pediatrics. The technique makes use of wearable ergonomic motion feedback sensors that detect and record hand movement in terms of position and speed of the fingers and wrist. Virtual functional tasks in the form of games present the patient with a series of movement instructions with the patient being encouraged to move their fingers according to the task. As the patient moves his hand a continuous stream of augmented feedback on the position and speed of movement is generated. A motion feedback learning loop is set up as the patient continually receives information on the quality of their movement as well as ongoing instructions on which movement to do. This feedback allows the patient to correct and influence his movement in real time according to the task.

The virtual functional tasks within an impairment oriented training system are goal oriented and can be customized to the patient’s movement ability. In this way, the patient stays motivated to do intensive practice at an exercise difficulty level or task difficulty level that is slightly above their movement ability. Extrinsic motion feedback is therefore used to encourage and motivate the patient to do repetitive intensive movements. This reinforces the correct arm movement pattern.

In cases when the patient does not have the range of movement ability to perform the exercise, the therapist or care giver can assist the patient in the required movement until the patient improves their movement ability. This is classified as Assisted Active Exercise Practice.

In this same way the dedicated rehabilitation tasks can be customized to patients that have a higher level of movement ability. In this case, the task practice will work on limits of the patient’s movement ability by setting a task that requires full finger extension and flexion and as fast an opening or closing movement as the patient can achieve. These limits of movement ability can not be practiced by TSP.

The impairment oriented training with augmented feedback has been shown to increase hand and arm functional ability following both continuous high and low intensity rehabilitation in a hospital, community clinic or home care setting http://bit.ly/dRBwqp

This Months Featured Authors and Vendor: Alan Waterman, Avraham Cohen and MediTouch Ltd, Israel

We thank our authors and MediTouch Ltd. for providing us with this article for our Monthly newsletter.

MediTouch manufactures the HandTutor system an ergonomic glove and dedicated rehabilitation software that incorporates the concept of Impairment Oriented Training (IOT) and augmented motion feedback. The HandTutor system has recently been sold to the pediatric OT department at the Rusk Institute of Rehabilitation Medicine. The HandTutor is also being used by private occupational and physical therapists and home care patients

Please support our Vendors by visiting their website at MediTouch, LTD. and read Alan Waterman's Blog at http://handtutorblog.wordpress.com

Tags: Article PT Newsletter 31 December 2010 Cerebral Palsy